Four circles

1) Calculate the circle radius if its area is 400 cm square
2) Calculate the radius of the circle whose circumference is 400 cm.
3) Calculate circle circumference if its area is 400 cm square
4) Calculate the circle's area if perimeter 400 cm.

Diameter What is the inside diameter of the cylinder container and if half a liter of water reaches a height 15 cm?

Lawns Before a sports hall are two equally large rectangular lawns, each measuring 40 m and 12 m. Maintenance of 10m² lawn cost 45 CZK yearly. On each lawn is circular flowerbed with a diameter 8 meters. How much money is needed each year to take on lawn care?.

Sidewalk The city park is a circular bed of flowers with a diameter of 8 meters, around it the whole length is 1 meter wide sidewalk . What is the sidewalk area?

Mine Wheel in traction tower has a diameter 2 m. How many meters will perform an elevator cabin if wheel rotates in the same direction 66 times?

Flowerbed In the park there is a large circular flowerbed with a diameter of 12 m. Jakub circulated him ten times and the smaller Vojtoseven times. How many meters each went by and how many meters did Jakub run more than Vojta?

Well Rope with a bucket is fixed on the shaft with the wheel. The shaft has a diameter 50 cm. How many meters will drop bucket when the wheels turn 15 times?